Metallurgical Effect of Rare-Earth Lanthanum Fluoride and Boride in the Composite Coating of Wires in the Arc Welding of Bainitic-Martensitic and Austenitic Steel

Abstract

For arc welding of high-strength and cold-resistant steels, the author developed an advanced design of steel wire with a micro-composite coating of a nickel matrix and nanoparticles of LaF3 and LaB6, which improves the metallurgical influence of rare-earth elements (REE) and forms refractory sulphides and oxides of REE, as well as boron nitride. The addition of 0.1–0.3 wt% La in the weld pool leads to an increase in the content of the refractory compounds La2O3, LaO2, and LaS, and to the reduction in the content of the low-melting and brittle oxides and sulphides SiO2, SiO, MnO, MnS, and SiS. The use of steel wire with the composite coating of LaF3 and LaB6 allows for microstructural refinement when welding S960QL bainitic-martensitic steel and X70 API bainitic steel, and increases the impact toughness of the welds by 1.17–1.6 times.

Dependence of Structural and Optical Performance of Lanthanum Fluoride Antireflective Films on O Impurities

“…It was widely used in the fluoride-glass ceramic [16,17], the scintillation crystals and rare earth crystal laser materials required by high-energy physics, nuclear medical imaging and industrial CT [18][19][20], arc lamp carbon electrode for lighting and other photoelectric fields, etc. [21][22][23]. Moreover, it has a low refractive index (1.4-1.6, compared with the Ge substrate) and low price.…”

Thermophysical Properties of Electric Arc Plasma and the Wire Melting Effect with Lanthanum and Sulfur Fluorides Addition in Wire Arc Additive Manufacturing

“…Kataoka et al [36] reported the possibility of spray transfer in CO 2 using REM added wire. Parshin et al [37,38] achieved an increase in impact energy of welds in arc welding high-strength steels using composite coated wire with LaF 3 -LaB 6 . Parshin et al [39][40][41][42] investigated the positive effect of CaF 2 , AlF 3 , KBr, KF, NaCl, BaCl 2 , TiO 2 on increasing the melting coefficient of wires and improving the droplet transfer parameters in the MIG-, MAG-welding of steels and aluminum alloys.…”